Variable leverage brake rigging



May' 3, 1938. B. H. BROWALL 2,116,010

- VARIABLE LEVERAGE BRAKE RIGGING Filed Feb. 28, 1935 3 Sheets-Sheet l y3, 1938. B. H. BROWALL 2,116,010

VARIABLE LEVERAGE BRAKE RIGGING Filed Feb. '28, 1935 5 Sheets-Sheet 2 y1938. B. H. BROWALL 2,116,010

VARIABLE LEVERAGE BRAKE RIGGING Filed Feb. 28, 1955 s Sheets-Sheet slure/27%) ram aj/ 6i zw Patented May 3, 1938.,

um'reo STATES 2,116,010 VARIABLE LEVERAGE BRAKE RIGGING Bert HenryBrowall, Malmo,

Aktiebol to Svenska Malmo, Sweden,

Sweden, assignor aget Bromsregulator,

a corporation of Sweden Application February 28, 1935, Serial No. 8,746

r 6 Claims.

This invention relates to equalized vehicle brake riggings, especiallyrailway freight car brake riggings, of the type in which the two mainpull rods which are connected to the free ends of the cylinder andfloating levers, respectively, and extend towards the opposite ends ofthe car, respectively, are disposed on opposite sides of thelongitudinal axis of the car, and in which, therefore, the floatinglever is inverted in relation to the cylinder lever.

The principal object of the invention is to provide an improved variableleverage arrangement for equalized brake riggings of the said type.Another object of the invention is to provide in equalized brakeriggings of the said type an improved variable leverage arrangement ofthe general character described and illustrated by Setterwall in the U.S. Patent No. 1,949,187, dated February 27, 1934, in which, for thepurpose of selectively producing different brake applying leverages, oneor more auxiliary levers are connected between the cylinder and floatinglevers to which the main pull rods are connected. More particularly, theinvention has for its object to provide a variable leverage arrangementwhich can be built in moreeasily and to greater advantage in brakeriggings of the said type on cars new existing. where the brake rigging,as originally constructed, has an invariable brake applying leveragesuited to the empty weight of the car, and where the brake cylinder andthe fixed fulcrum of the floating lever are so disposed that theconnection rod between the cylinder and floating levers is substantiallyparallel to the longitudinal axis of the car. In such a case, if anattempt is made to build in the variable leverage arrangement of theconstruction shown, for instance, in Fig. 3 or Fi drawings of the saidU. S. 'Patent between the cylinder and floating out otherwise changingthe brake tain difliculties will be met with.

It is the object of the invention to reduce or eliminate thesediflficulties orderthat the nature of the advantages gained thereby mstood, the nature of the said difliculties will be declared in thefollowing with reference to Figs. 1 and 2 on the accompanying drawings.

In the accompanying drawings:

Figs. 1 and 2 illustrate diagrammatically and in plan view the variableleverage arrangement as constructed accordin ..respectively, in the saidU..S. Patent No. 1,949,187,

rigging, .cer-

invention and the ay be fully underg. 4 in the No; 1,949,187,, loverswithand, therefore, in

g to Fig. 3 and Fig. 4,

but as applied to an existing brake rigging of the kind referred toabove. 1 1

Figs. 3 and 4 illustrate diagrammatically and in plan view twoconstructional forms of the invention as applied to. a brake rigginghaving a Variable leverage arrangement similar to that shown in Fig. 1and Fig. 2, respectively.

Fig. 5 illustrates in the same way another manner of realizing theprinciple underlying the invention.

Fig. 6 is a detail section on a larger scale of parts shown in Fig. 5.

Fig. 7 illustrates diagrammatically and in plan view a furtherconstructional form of the invention. 1

Fig. 8 illustrates in the same manner still another constructional formof the invention.

Referring to Figs. 1 and 2, i represents the brake cylinder and 4 and I!the cylinder and floating levers, respectively, which in the originalconstruction of the brake, rigging are interconnected by means of aconnection rodlinked to the said levers in the points 31 and 38,respectively, so that these points divide the two levers in equalleverage ratios K respectively, suited to the empty weight of the car.The main pull rod 56!. connected to the free end of the floating lever Il and the main pull rod 51) connected to the cylinder lever 4 aredisposed on opposite sides of the longitudinal} axis of the car and,consequently, the cylinder j lever and the floating lever extend towardsopposite sides of the car from the brake piston head 2 and the fixedfulcrum 3, respectively, the construction being such that the aforesaidconnection rod between the cylinder and floating levers is substantiallyparallel to the longitudinal axis of the car.

In building in the variable leverage arrangement in the said existingbrake rigging the aforesaid original connection rod between the cylinderand floating levers is substituted by a connection rod l2 or 20 which islinked to the cylinder lever and an auxiliary lever 7 or I8 in thepoints 3'! and I I as shown in Figs. 1 and 2, respectively, and afurther brake lever connection 8 1 or 22 is established betweenthecylinder lever and another auxiliary lever 6 as shown in Fig. l, orbetween the cylinder lever 4 and the same auxiliary lever l8 as shown inFig. 2. This further connection 2 and operativealternately with theconnection rod I2 or 20 by means of the switchable abutment I5, islinked to the cylinder lever 4 in a point 39 dividing the said lever ina leverage ratio suited to loaded car. The floating lever I1 isconnected to said auxiliary levers or lever B, I or l8 by an articulatedor single link rod Illa, or 220., respectively, which is linked to thefloating lever I! in a point 48 dividing said lever in such a leverageratio 75 that the pulling force transmitted to the pull rod 511 at abraking operation will be equal to the pulling force transmitted to thepull rod b, irrespective of whether the transmission of the brakingpower takes place at the lower leverage ratio suited to empty car, or atthe higher leverage ratio suited to loaded car.

Considering the construction as shown in Fig. 1, in which the leversBand 1 have the leverage ratios 2 and a 21 a respectively, the followingrelations will be found. (a) Braking at the lower leverage ratio suitedto empty car. The shiftable abutment I5 is then in the right handposition and supports the end of the lever I. The lever B is unsupportedand non-operative. 'Ihe pull on rod P designating the force from thepush rod of the brake cylinder. The pull on rod 5a: (1) In the originalcondition with rod l2 connected directly to point 38 I a+b a .3 QaE- bI+ I b (2) In the altered condition in which the auxiliary levers B and1 are added according to the U. S. Patent No. 1,949,187, and the endportion of rod l2 adjacent the lever I1 is replaced by rod la. Thevalues of n and 0 must 'be selected so that the pull on rod 50. willstill be equalto a P'Z; The pull on rod So can be expressed by theequation a+b 31 o QEP b n c+d wherein c'+d'=a+b'.

Obviously the condition the left hand position and supports the lever 6,

while the lever l is unsupported and nonoperative.

It may be shown in the same manner as above that the condition for equaloutput forces of the cylinder lever and the floating lever is exactlythe same as that expressed by the equation 2 jc a b It is thus to beseen that although the known 7 construction certainly is operative, itsapplication on existing cars leads to the drawback that the olm it willbe found that in order to obtain equality in respect of the pullingforces in the two pull rods 5a and 5b when braking at the higherleverage ratio as well as when braking at the lower leverage ratio, theconnection rod 22a by necessity must take an oblique position. Suchobliquity is undesirable due to the lateral stresses or loads on thefulcrums and the piston head 2 resulting therefrom.

The present invention has for its object to avoid obliquity in the brakerigging, while maintaining a proper action of the variable leveragearrangement for selectively producing the desired different brakeapplying leverages. This result is obtainable, when applying theinvention to an existing brake rigging of the kind set forth withreference to Figs. 1 and 2 herein, by connecting the connection rod IOaor 22a not to the floating lever I! but to an additional lever which hasa fixed fulcrum disposed substantially on the axis of the brakecylinder, and by connecting the floating lever IT to the said additionallever.

Referring to Figs. 3 and 4, the same reference characters are usedtherein as in Figs. 1 and 2, respectively, for corresponding detailsand, therefore, it will be unnecessary to describe again such details asalready have been described with ref erence to Figs. 1 and 2. It is tobe noted, however, that the connection rod a in Fig. 3 and .22a in Fig.4 is connected to the free end of an additional lever 42 having a fixedfulcrum 43 disposed substantially on the axis la of the brake cylinderI. The length of this additional lever 42 is equal in Fig. 3 to n and inFig. 4 to c. The additional lever 42 and the floating lever H areinterconnected by means of a connection rod Hlb in Fig. 3 and 22b inFig. 4, which is linked to the floating lever H in the point 38 and tothe additional lever 42 in a point at a distance ya from the pivot point43. This construction works properly for selectively producing thedesired different brake applying leverages and gives the desiredequality in respect of the pulling forces transmitted to the two mainpull rods 5a and 5b when braking at the higher leverage ratio as well aswhen braking at the lower leverage ratio, as may be shown in the samemanner as in the case of the known construction in Fig. 1, whileobtaining the desirable parallelism of all the connection rods in theconstruction.

The invention, however, can also be realized in a manner resulting in amuch more simple conbetween the fixed fulcrum 43 for a brake applyingleverage "used in the constructions hereinbefore described forselectively producing the desired different An example of such shown inFig. 5 on in which the same brake applying leverages. a simplifiedconstruction is the accompanying drawings,

reference characters are used as in Figs. 3 and 4 for correspondingdetails. According to this constructionthe original connection rodbetween the points 31 and 38 on the cylinder and floating levers 4*andII, respectively, is divided into two parts 44 and 45.

The part 44 is connected between the point 3'! on the cylinder lever 4and a point 46 on an additional lever 42, and the part 45 is connectedbetween the said point 46 and the point 38 on the floating lever I1. Thedistance the lever 42, which {is disposed on the axis la tance betweenthe piston head 2 and the point 37 on the cylinder lever 4, so that the"rods 44 and 45lwill be substantially parallel to the longitudinal axisof the car. on' the cylinder lever 4, inder lever in a leverage Betweenthe point 4'! which divides the cylratio adapted to give suited toloaded car, and the point 49 on the additional lever 42 there isestablisheda connection 48, the distance between the point 49 and thefixed fulcrum 43 being equal to the distance between the point 41 andthe pistonhead 2. In the rod 44 there is provided a device for settingthis rod in and out of action for selectively producing the desireddifferent brake applying leverages, the lower leverage for empty carbeing obtained when the said rod44 is active as a power transmittingmember at brakin and the higher leveragefor loaded car being obtainedwhen the said rod 44 is made inactive so that the power transmission istaken over by the connection rod 48. In the example shown the saiddevice is in the form of a so called rod coupler having a couplingmember 50 which is movable in and out of active position in which itcouples the rod 44 to the lever 42, by means of a link 52, a bell cranklever 53 pivoted on the fixed fulcrum 43, a link 54 and a crank arm 55on a transverse shaft 56. This shaft 56 may extend to the sides of thecar and be provided with crank handles for setting the coupling member50 manually, or a device of any suitable kind may be provided forsetting the coupling member automatically in dependence upon the load ofthe car, for instance a device of the character disclosed in the Germanpatent specification No. 598,085. Preferably the rod coupler is soconstructed that when in active position it leaves a certain slack 5| inthe rod 44. This slack serves the same purpose as do the slacks providedfor by the elongated holes 13 and I9 in the constructions shown inFigs.' 1-4 herein, and the purpose of these slacks may not be describedhere since it is evident from the specification pertaining to thehereinbefore mentioned U. S. Patent No. 1,949,187 and forms no featureof the present invention. In the rod 48 there is provided an elongatedhole 57 for at least one of the connection bolts 4'! and 49 in order toallow for the relative movement of the points 47 and 49 towards eachother, which takes place when braking at the lower leverage ratio.

When pivoting the coupling member 50 on the bolt. 46 by which theconnection rod 45 is fasof the brake cylinder and the point 46, is equalto the distened to the lever 42, most favourable disposal of the strainson the bolt is obtained if the pivoted end of the coupling member 50 isbifurcated and embraces the bifurcated adjacent end of the rod 45, asshown in Fig. 6. For the rest the construction of the device forselectively setting the connection rods 44 and 48in and out of actionforms no part of the present invention, and this device maybeconstructed in any suitable manner or be of any suitable type, forinstance of the type described and shown in the co-pcnding applicationSer. No. 752,167, filed November 8, 1934, or of the type disclosed inthe French Patent No. 762,438 or of the type disclosed in co-pendingapplication Ser. No. 15,691 filed April 10, 1935. Further there isno-hindrance to providing each of the rods 44 and 48 with a device forpositively setting the rod in and out of action, and for such purposedevices of the characters disclosed in the U. S. Patents Nos. 1,963,224and 1,980,328 may be used. Of course it is also possible to provide morethan two connection rods between the cylinder lever 4 and the additionallever 42 for selectively producing more than two different leverageratios, if desired. Such a constructional form of the invention isillustrated in Fig. 7, in which, in addition to the connection rod 48,there are two connection rods 44' and 44" connected tothe cylinder lever4 at 31'and 37", respectively, and

adapted to cooperate with rod couplers 50 and 54", respectively, whichare pivoted to the additional lever 42 and are operable selectively bymechanism 52', 53', 54', and 52", 53", 54", re-

spectively. Finally the connection between the cylinder lever 4 and theadditional lever 42 can also be constructed in such a way as to makepossible a progressive variation of the brake applying leverage, forinstance by adopting a variable leverage mechanism substantially of thecharacter disclosed in the U. S. Patent No. 621,653

or of the character disclosed inthe U. S. Patent No. 1,937,267. Fig; 8illustrates a constructional form of the invention, in which thecylinder lever 4 and the additional lever 42 are interconnected by meansof a connection rod 59 which is secured to the levers by means of pins60 engaged in elongated slots 6! in the levers and slidable therein by amechanism 62 as disclosed in the aforesaid US. Patent No. 621,653, forthe purpose of progressive variation of the leverage ratios of the twolevers 4 and 42. In allthese cases the invention enables all theconnection rods to be disposed in parallelism to the longitudinal axisof the car.

If it should be desirable, for some reason or the other, to abstain fromlinking both the rods 44 and 45 to the same point 46 on the additionallever 42, it is permissible to displace the connecting point of the rod45 on the lever 42 a small distance towards or away from the fixedfulcrum 43. When doing so also the connecting point 38 for the rod 45 onthe floating lever I! should be displaced a corresponding distancetowards or away from the fixed fulcrum 3 of the lever ll. If, in such acase, the object is to build in the variable leverage arrangement in anexisting brake rigging where it is impossible to alter the localposition of the entire lever I! by a parallel-displacement thereof, orto alter its total length, the rod 45 will take a somewhat obliqueposition, but the lateral stresses arising therefrom will be taken up bythe fixed fulcrums 3 and 43 and will have no influence upon the pistonhead 2. In the construction of new cars, however, it is possible toselect such a position for the fixed fulcrum 3 andlor such a length ofthe lever I! that the connecting point 38 on the lever I! will be soaligned with the displaced connecting point for the rod 45 on the lever42 that the rod 45 is maintained in parallelism to the other connectionrods.

What I claim and desire to secure by Letters Patent is:-

I. In a variable leverage brake rigging of the character described, abrake cylinder, a cylinder lever, a floating lever, an additional lever,a, nonshiftable fulcrum for said additional lever disposed substantiallyon the axis of the brake cylinder, means for simultaneously varying theleverage ratio of the cylinder lever and the additional lever, and aconnection between the additional lever and the floating lever, saidconnection being substantially parallel to the axis of the brakecylinder and so arranged in relation to said floating and additionallevers, that the output force of the floating lever will besubstantially equal to the output force of the cylinder lever for boththe high and low leverage setting of the brake rigging.

2. In a variable leverage brake rigging of the character described, abrake cylinder, a cylinder lever, a floating lever, an addtional lever,a nonshiftable fulcrum for said additional lever at a fixed pointdisposed substantially on the axis of the brake cylinder, means forselectively producing diiferent brake applying leverages connectedbetween said additionallever and the cylinder lever, and a connectionbetween said additional lever and the floating lever, said connectionbeing substantially parallel to the axis of the cylinder lever and soarranged in relation to said floating and additional levers, that theoutput force of the floating lever will be substantially equal to theoutput force of the cylinder lever for both the high and low leveragesetting of the brake rigging.

3. In a variable leverage brake rigging of the character described, abrake cylinder, a cylinder lever, a floating lever, an additional lever,a nonshiftable fulcrum for said additional lever at a fixed pointdisposed substantially on the axis of the brake cylinder, a plurality ofconnections between said additional lever and the cylinder lever forselectively producing different brake applying leverages, and aconnection between said additional lever and the floating lever, saidconnection being substantially parallel to the axis of the brakecylinder and so arranged, that the output force of the floating leverwill be substantially equal tothe output force of the cylinder lever forboth the high and low leverage setting of the brake rigging.

4. In a variable leverage brake rigging of the character described, abrake cylinder, a cylinder lever, a floating lever, an additional lever,a nonshiftable fulcrum for said additional lever at a fixed pointdisposed substantially on the axis of the brake cylinder, substantiallyaligned connections between the cylinder lever and the additional leverand between the latter and the floating lever, respectively, and meansincluding said connection between the cylinder lever and the additionallever for simultaneously varying the leverage ratio of the cylinderlever and the additional lever, said substantially aligned connectionsbetween the cylinder lever and the additional lever and between thelatter and the floating lever being substantially parallel to the axisof the brake cylinder and so arranged, that the output force of thefloating lever will be substantially equal to the output force of thecylinder lever for both the high and the low leverage setting of thebrake rigging.

5. In a variable leverage brake rigging of the character described, abrake cylinder, a cylinder lever, a floating lever, an additional lever,a nonshiftable fulcrum for said additional lever at a fixed pointdisposed substantially on the axis of the brake cylinder, a connectionrod between the cylinder lever and the additional lever connected to thecylinder lever in a point dividing the cylinder lever in a lowerleverage ratio, a second connection rod between the cylinder lever andthe additional lever connected to the cylinder lever in a point dividingthe cylinder lever in a higher leverage ratio, a connection rod betweenthe additional brake lever and the floating lever connected to thelatter in a point dividing the same in a leverage ratio equal to thesaid lower leverage ratio of the cylinder lever, all the said connectionrods being substantially parallel, and means for selectively setting thesaid connection rods between the cylinder lever and the additional leverin and out of action at braking.

6. In a variable leverage brake rigging as claimed in claim 5, theadditional feature that the said means includes a coupling member havinga bifurcated end pivoted on a fastening bolt on the additional lever forthe connection rod between the latter and the floating lever andembracing the adjacent end of said connection rod.

BERT HENRY BROWALL.

